National Affairs: The New Threat

Into the boiling debate over nuclear testing stepped an internationally
known nuclear physicist and mathematician, Freeman John Dyson, 36,
British-born, Cambridge-educated professor at the Institute for
Advanced Study at Princeton. Writing in Foreign Affairs, Dyson insisted
that the U.S. must spurn an uncheckable test ban and resume testing.
His key reasons:

¶ The big powers are on the brink of developing radically new
generations of cheaper, cleaner, lighter, militarily more important
nuclear weapons. ¶ Testing of weapons of less than megaton size
(equivalent to 1,000,000 tons of TNT) could easily escape long-range
detection.